Action: Reduce conflict by deterring birds from taking crops using repellents
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A replicated, randomised and controlled ex situ study in the USA found that dickcissels Spiza americana consumed less rice if it was treated with two repellents, compared to controls. Two other repellents did not reduce consumption as effectively.
In some parts of the world, the persecution of birds that take crops can be a serious threat to the survival of populations. Methods to reduce the damage done by birds can therefore be important in reducing the pressure on populations.
Supporting evidence from individual studies
A replicated, randomised and controlled ex situ study in the USA (Avery et al. 2001) found that dickcissels Spiza americana captured in Venezuela consumed 70% less rice if it was treated with methiocarb (at 0.05 g/g rice) or anthraquinone (0.5 g/g), compared to control (untreated) rice offered previously. Methyl anthranilate and lower doses of anthraquinone did not reduce consumption of rice when treated rice was offered after untreated rice. However, when a choice of rice treated with 0.05% or 0.1% anthraquinone or untreated millet was offered at the same time, birds significantly reduced their consumption of rice, with the preference growing over eight days of testing. Rice was offered over five days (control rice on the first, followed by treated rice), with rice and millet being offered over eight days. The number of birds tested is not provided.